Optical transition and ionicity of C-60/amine charge-transfer complexes studied by optical spectroscopy

We have investigated absorption spectra of charge-transfer (CT) complexes o f C-60 with various aromatic amines with different ionization potentials. A n absorption band due to CT transition is observed in the visible region; w ith increasing ionization potential of amines, the peak energy shifts to th e higher energy side and the oscillator strength of CT transition increases . We extract degrees of charge transfer by analyzing the transition energy of the CT band as a function of ionization potential and Raman spectra. The experimental results show that the CT complexes studied here have a neutra l character in their ground state. (C) 1999 Elsevier Science B.V, All right s reserved.